Muscle is like a car: It needs fuel to function. If your muscles are running on an empty gas tank, they can't grow, and what's worse, they'll actually go in reverse. Eat at least six small meals a day, getting plenty of protein and complex carbs to ensure you have the energy and capacity to build muscle.

FIRE

High-intensity training that focuses on engaging multiple muscle groups simultaneously and always keeps your muscles wondering - that's the key to making muscles grow. Keep your muscles firing and challenged and they'll keep on responding; do the opposite and you'll stop making gains.

FRESH

Muscle that doesn't have time to recover doesn't have time to rebuild and grow. Work out hard, but then take time to relax and refresh yourself. You'll often find your greatest muscle gains come during time off; slave away in the gym day after day with no break, and you'll get burned out and burned up in no time.